On Mon, 21 Jul 2008 12:09:10 -0700, "David Farber"
put finger to keyboard and composed:

Franc Zabkar wrote:

If it's attached to the heatsink, then I would think it would be an
NTC thermistor. Heat it up with a hair dryer and check for a drop in
its resistance. I think you'll find that temperature controlled CPU
fans are quite common these days.

If the device is a fuse (unlikely), then one end would probably be
connected to the supply pin (or to ground).

You could also bypass the device with a low resistance, say 100 ohms,
if only for testing purposes.

- Franc Zabkar

Hi Franc,

Heating it up drops the resistance slightly. One terminal is hooked up to
the red wire marked "V." So it appears it is a thermal fuse. I temporarily
bypassed it and now the motor spins up.

If there is no other connection to the red wire, then it would seem
that the fan is getting its power via that device, in which case it
must be a fuse. If it is a fuse, and if the motor spins up straight
away, ie without waiting for the heatsink to warm up, then the fan
can't be a temperature controlled type.

- Franc Zabkar
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